| First Author | Szczypka MS | Year | 1999 |
| Journal | Proc Natl Acad Sci U S A | Volume | 96 |
| Issue | 21 | Pages | 12138-43 |
| PubMed ID | 10518589 | Mgi Jnum | J:58125 |
| Mgi Id | MGI:1346754 | Doi | 10.1073/pnas.96.21.12138 |
| Citation | Szczypka MS, et al. (1999) Feeding behavior in dopamine-deficient mice. Proc Natl Acad Sci U S A 96(21):12138-43 |
| abstractText | Mice that cannot make dopamine (DA), a condition caused by the selective inactivation of tyrosine hydroxylase in dopaminergic neurons, are born normal but gradually become hypoactive and hypophagic, and die at 3 weeks of age. We characterized the feeding and locomotor responses of these DA-deficient (DA-/-) mice to 3, 4-dihyroxy-L-phenylalanine (L-DOPA) to investigate the relationship between brain DA levels and these complex behaviors. Daily administration of L-DOPA to DA-/- mice stimulated locomotor activity that lasted 6 to 9 hr; during that time the mice consumed most of their daily food and water. The minimal dose of L-DOPA that was sufficient to elicit normal feeding behavior in the DA-/- mice also restored their striatal DA to 9.1% of that in the wild-type (WT) mice at 3 hr; then DA content declined to <1% of WT levels by 24 hr. This dose of L-DOPA induced locomotor activity that exceeded that of treated WT mice by 5- to 7-fold, suggesting that DA-/- mice are supersensitive to DA. Unexpectedly, DA-/- mice manifested a second wave of activity 24 to 48 hr after L-DOPA treatment that was equivalent in magnitude to that of WT mice and independent of DA receptor activation. The DA-/- mice approached, sniffed, and chewed food during this second period of activity, but they ate <10% of that required for sustenance. Therefore, DA-/- mice can execute behaviors necessary to seek and ingest food, but they do not eat enough to survive. |
